Clinical outcome of submerged vs. non-submerged implants placed in fresh extraction sockets

The aim of this study was to compare the clinical outcome of submerged vs. non-submerged tapered implants placed into fresh extraction sockets.

A prospective, controlled, multicenter, randomized, clinical trial has been performed in two centers in Rome and Torino (Italy). Thirty healthy patients were recruited according to the following inclusion criteria: need for an immediate post extraction implant, ages between 18 and 70, horizontal defect depth <2 mm, smokers <10 cigarettes/day and absence of any circumstance or condition that could represent contraindications to implant surgery. The patients were randomly allocated to submerged or non-submerged treatment groups immediately after flap elevation and tooth extraction. Submerged implants were exposed 8 weeks after the first surgery; all implants were loaded with provisional restorations 12 weeks after the first surgery and with definitive restoration 12 weeks thereafter. Clinical and radiographic parameters were evaluated at baseline, at implant loading and at the 1-year follow-up visit.

The results showed statistically significant differences between the two groups in the mean value of keratinized tissue (KT) height after surgery that was significantly reduced for submerged implants when compared with transmucosal implants (mean reduction of KT at year follow-up: T group 0.2 mm, S group 1.3 mm; P=0.007).

Similar outcomes were found for submerged and non-submerged implants placed in fresh extraction sockets with a horizontal peri-implant defect smaller than 2 mm, except for a reduction of KT in the submerged group. Either with a submerged or a non-submerged procedure, 1 mm of mean soft tissue recession is seen after 1 year when compared with the pre-extraction situation.